AIC1574 AIC [Analog Intergrations Corporation], AIC1574 Datasheet - Page 16

• Manufacturer Part Number: AIC1574
• Description: 5-bit DAC, Synchronous PWM Power Regulator with Triple Linear Controllers
• Manufacturer: AIC [Analog Intergrations Corporation]

A multi-layer-printed circuit board is recom-
mended. Figure 11 shows the connections of
the critical components in the converter. The C
and C
physical capacitors. Dedicate one solid layer for
a ground plane and make all critical component
ground connections with vias to this layer.
PWM Output Capacitors
The load transient for the microprocessor core
requires high quality capacitors to supply the
high slew rate (di/dt) current demand.
The ESR (equivalent series resistance) and ESL
(equivalent series inductance) parameters rather
than actual capacitance determine the buck ca-
pacitor values. For a given transient load magni-
Table 1 VOUT1 Voltage Program (0=connected to GND, 1=open or connected to 5V)
VID4
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
OUT
VID3
could each represent numerous
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
PIN NAME
VID2
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
VID1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
VID0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
For all package versions
VOLTAGE
DACOUT
IN
1.80 V
1.85 V
1.90 V
1.95 V
2.00 V
2.05 V
1.30V
1.35V
1.40V
1.45V
1.50V
1.55V
1.60V
1.65V
1.70V
1.75V
VID4
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
tude, the output voltage transient change due to
the output capacitor can be note by the follow-
ing equation:
After the initial transient, the ESL dependent
term drops off. Because the strong relationship
between output capacitor ESR and output load
transient, the output capacitor is usually chosen
for ESR, not for capacitance value. A capacitor
with suitable ESR will usually have a larger ca-
pacitance value than is needed for energy stor-
age.
A common way to lower ESR and raise ripple
V
I
OUT
OUT
VID3
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
is transient load current step.
ESR
PIN NAME
VID2
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
I
OUT
VID1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
ESL
VID0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
I
OUT
T
VOLTAGE
AIC1574
,
DACOUT
INHIBIT
2.1 V
2.2 V
2.3 V
2.4 V
2.5 V
2.6 V
2.7 V
2.8 V
2.9 V
3.0 V
3.1 V
3.2 V
3.3 V
3.4 V
3.5 V
where
16